A German court has charged a 96-year-old former SS officer for “knowingly and willingly” contributing to mass murder in a Nazi death camp in Poland. The man is also accused involvement in the killing of thousands in “Operation Harvest Festival.”

The man, who has not yet been named, was employed between August 1943 and January 1944 at the Majdanek Concentration Camp, operated by the SS during the German occupation, near the Polish city of Lublin.

He was 22 when he started working at the death camp as a member of the fifth company of the SS Death’s Head unit, Frankfurt-am-Main prosecutors said in a statement on Friday.

The SS Death’s Head unit was responsible for administering concentration camps for the Third Reich.

The 96-year-old, now a resident of Frankfurt-am-Main, was tasked with “securing the camp and guarding the prisoners to be killed,” the statement from the prosecutors said.

“According to available information, the accused, as well as other SS members of the camp, knew about the cruelty of the organized mass killings. He should have known that people, who were fiercely opposed to their fate, were killed out of racial despicable motives.”

In particular, the former SS guard was accused of being involved in the so-called “Operation Harvest Festival” which took place in November 1943.

Some 18,000 Jews, including the camp prisoners and detainees of Nazi labor camps, were shot outside the camp, according to the data from US Holocaust Memorial Museum (USHMM). During the mass murder, music was reportedly played over loudspeakers to mask the sounds of the massacre.

“He knowingly and willingly contributed to these insidious and cruel acts,” the prosecutions added.

According to USHMM data, the SS killed tens of thousands of Jews at Majdanek, which had between 74,000 and 90,000 prisoners living in inhumane conditions. Sometimes SS guards shot prisoners who were too weak to work; many of them were exterminated in gas chambers.

The camp was liberated in July 1944 by Soviet forces.

Germany has previously only prosecuted Nazi war criminals if evidence showed they had personally committed the crimes.

However, in a 2011 landmark ruling, Germany sentenced voluntary SS assistant Ivan Demjanjuk to five years in prison after he was found guilty of complicity in some 30,000 Jewish deaths in German-occupied Poland during World War II.

Earlier in October a German court found Ursula Haverbeck, also known as ‘Nazi Grandma’, guilty of inciting hatred by saying that Holocaust is fiction and there were no gas chambers in the Auschwitz concentration camp. She was handed a six-month jail sentence.